It is known in the prior art to carry telephone calls between local telephone operating companies through the AT&T network or through one or more independent inter-exchange carriers such as MCI or Sprint. The local telephone operating companies operate within a so-called local access and transport area (LATA). When a long distance call is dialed, the call is usually transmitted through an operating company central office to a point of termination in the originating LATA at which it is picked up by the inter-exchange carrier and passed by that carrier on to a termination point in a distant LATA. Upon reaching the destination LATA, the call is then transferred by the inter-exchange carrier to the local operating company central office within that LATA for ultimate connection to the original called station therein. Typically, the termination points of each LATA include suitable switching circuits, e.g., an access tandem, that are interconnected by a digital serial link. Such digital links are also presently used to interconnect virtually all central offices as well as to interconnect operating company switching networks to one or more cell site control switches of a mobile telephone network.
It is also known in the prior art to provide "automatic voice messaging" where, upon the occurrence of a busy/ring-no-answer condition at a called station, the user of the calling station can be connected to a voice message facility for recording a voice message for subsequent delivery to the called station. The decision to accept or reject the automatic voice messaging service is determined by the caller. Automatic voice messaging operates essentially after a call has been initiated but before the call can be completed to the called station.
It would be desirable to extend the advantages of caller-controlled automatic voice messaging to facilitate the providing of enhanced proactive services after call completion.
Numerous subsystems exist in the network. Although not meant to be limiting, examples of these subsystems include cellular networks, traffic operator position systems (TOPS) and other switches associated with a public-switched network (PSN). For example, a cellular network subsystem processes calls and transfers them into the local exchange carrier's PSN. A TOPS handles calls beginning with "0" utilizing automated processes (such as calling card billing systems) and forwards the calls into the main "1+" long distance network.
Most subsystems have their own billing and metering systems (such as cellular). A problem associated with the provision of proactive call services is the "closed nature" of the subsystems comprising the existing telephone network. The subsystems are architecturally "closed," in that they are designed to prevent equipment outside the original architecture of the subsystem to interfere with a call in process inside the subsystem. Closed subsystems, such as an operator system with a base unit and supporting remote systems, work together to process a call, after which the call is passed through to the network so that it may terminate at the destination. A typical closed subsystem has computer interfaces for computer support (such as data bases for calling card verification) and stations for live operator support, but these interfaces do not generally allow for switching equipment to redirect the call from within the closed system or allow for additions, subtractions or modifications to the call in process, or otherwise allow for any other service which might be utilized to effect or redirect the call in process.
The closed subsystem is controlled by a master switching arrangement that sends calls to several subsupport slave facilities (live operators and voice processing systems, each supported by computer databases). The master switching arrangement creates billing records and is designed to be the only mechanism for processing (either manually or automatically) the call to pass via the "1+" system to its destination.
What is needed is a programmable interface to easily manipulate existing closed subsystems for the provision of proactive call services.